1. Field of the Invention
This invention relates to a method and membrane which removes .beta..sub.2 -microglobulin from blood in a hemodialysis procedure. More particularly, this invention relates to a membrane which selectively removes .beta..sub.2 -microglobulin when blood is purified by hemodialysis.
2. Description of the Prior Art
Long-term complications have been found to occur in patients undergoing hemodialysis for blood purification. These complications include osteopathy, anemia and carpal tunnel syndrome. Although countermeasures against these disorders have long been studied, they have been largely relatively ineffective. The belief is now spreading that some blood components cannot be removed or are not significantly removed by current hemodialysis procedures typically conducted by using a cellulosic membrane, and that they remain and accumulate in the blood and participate in causing long-term complications. However, these components have not yet been completely identified and even their participation in the complications has not yet been proved. The present inventors first proved that the carpal tunnel syndrome, from which patients undergoing hemodialysis often suffer, is caused by the deposition of amyloid fibers, and that a component of the amyloid fibers is .beta..sub.2 -microglobulin (Biochem. Biophys. Res. Commun. 129, pp. 701-706, 1985).
Heretofore, it has been attempted to remove uremic large and medium size molecules by using a dialysis membrane which permits the passage of proteins, instead of using a typical dialysis membrane which does not allow proteins to pass through. A number of such membranes have been developed. However, these membranes are used for the purpose of non-selectively removing uremic large molecules, and accordingly in some cases more than 20 g of proteins are removed in one dialysis. When such a membrane is continuously used there is a serious danger that the patient may develop hypoproteinemia.